1. Field of the Invention
The present invention relates to an apparatus for detecting the amount of paper remaining in a cassette of a printer and, more particularly, to an apparatus for detecting the amount of paper remaining in a cassette of a printer in which the remaining paper information is obtained as an electrical signal, to show the information by sending the information to a printer display and/or computer connected to a printer.
2. Description of the Related Art
In a typical electrophotographic printer such as a laser printer or a copying machine, an electrostatic latent image is formed on a photosensitive medium by exposure, and an image obtained from the electrostatic latent image developed by a developing material is transferred to a paper to print a desired image.
In the above printer, a paper cassette is provided for storing papers capable of moving into or out of a main body of the printer.
When there is no paper in the paper cassette, printing cannot be performed. Thus, before printing, the paper cassette is checked using a separate sensor to detect whether there is paper in the paper cassette or not, or by using a sensor for detecting whether paper to be supplied to a printing unit passes through a paper transferring path. In the case of using a sensor for detecting whether the paper passes through the paper transferring path, a paper feeding roller for feeding the paper of the paper cassette is driven, and then when a paper passing signal is not output from the sensor at a predetermined time, the printing is stopped. Meanwhile, when there is no paper in the paper cassette, a system controller sends a signal or a message on a display installed on an operation panel informing the user.
However, in the conventional technology, information on the amount of paper remaining cannot be obtained before exhaustion of paper.
A display may be provided in one side of the paper cassette to show the amount of paper remaining without opening the paper cassette. However, a remote user away from a printer or a user using the printer through a network must go to the printer to check the amount of paper remaining.